Tell git to ignore directory ownership (fixes #2495) (#2496)

* Tell git to ignore directory ownership in docker

* Show usage instead of an error when no arguments are passed into docker

entrypoint.sh

@@ -3,4 +3,11 @@
 # Parse the last argument into an array of extra_args.
 mapfile -t extra_args < <(bash -c "for arg in ${*: -1}; do echo \$arg; done")
 
-/usr/bin/trufflehog "${@: 1: $#-1}" "${extra_args[@]}" 
+# Directories might be owned by a user other than root
+git config --global --add safe.directory '*'
+
+if [[ $# -eq 0 ]]; then
+  /usr/bin/trufflehog --help
+else
+  /usr/bin/trufflehog "${@: 1: $#-1}" "${extra_args[@]}"
+fi